1. Field of the Invention
The present invention relates to an image capturing apparatus and control method thereof, and particularly relates to shooting techniques for shooting multiple images at different exposures.
2. Description of the Related Art
Some image capturing apparatuses that shoot objects, such as cameras, have autoexposure (AE) control, where the object is shot at a correct exposure obtained by adjusting the aperture, shutter speed, and so on in accordance with the brightness of the object. There is an assumption that the object to be shot is often present in the center of the image, and thus there are AE control techniques that use selective photometry of a brightness in the center of the image, detect a contrast within the image and adaptively select which of a bright region and a dark region to use in selective photometry, and so on. A landscape scene in which a bright sky is present in an upper area of the image and dark land is present in a lower area of the image, a backlit scene in which a dark person is present in the foreground and bright sunlight is present in the background, and so on can be given as examples of scenes where such contrast is present in the image. In such scenes, it is desirable to identify a main object that a user wishes to shoot and enable that main object to be shot at a correct exposure. However, realistically speaking, there are cases where the AE control cannot always be realized according to the intentions of the user, which results in a failure to achieve the intended exposure.
Automatic exposure bracketing (AEB), in which brighter and darker images whose exposures are shifted by a specified amount from the AE-determined exposure are shot along with the original image, is known as a technique for addressing such situations where the exposure determined through AE does not necessarily result in the user's intended composition. Shooting using AEB records multiple images at different exposures, and thus the user can select the image that best fits his or her preferences later on.
However, AEB requires the user to specify an exposure amount in advance, and thus users have been required to perform operations for making settings in accordance with each new scene.
For example, Japanese Patent Laid-Open No. 2008-104009 focuses on a luminance range of an image sensor, and discloses determining the exposure so that the exposure falls within the luminance range.
Japanese Patent Laid-Open No. 2008-104009 determines the exposure by focusing on the luminance range of the image sensor, and thus does not take into consideration factors such as the compositional intent, the photographic quality of the image, and so on used in determining the correct exposure for a given scene. For example, there are cases where an appropriate AEB amount when the face region of a person is present in the image, an appropriate AEB amount based on color information within the image, and so on cannot be determined, resulting in a sub-optimal image.